1. Field of the Invention
The invention relates to a Fresnel mirror for the directed reflection of light, in particular of sunlight and/or for directing of artificial light in illumination systems, as well as a method for producing such a Fresnel mirror.
2. Brief Description of the Background of the Invention Including Prior Art
A Fresnel lens is known, which exhibits a step shaped cross section and which was originally developed for lighthouses. The Fresnel step lens enables the construction of large lenses with short focal lengths, without the weight and volume of conventional lenses, since cheap Fresnel lenses can also be produced of plastic. Typical problems of plastic lenses are power losses based on environmental influences and mechanical damages based on bending through as well as temperature loading.
The application of the Fresnel principle is also known from the German printed patent document DE 102 48064. The solar tower power plant is shown in this printed patent document. The sunlight is reflected by a helio stat field is concentrated and absorbed in a tower absorber. The helio stat field comprises several individual mirrors, which are installed according to the Fresnel principle. This helio stat field reflects the sunlight always onto the same spatially fixed point independent of the change of the position of the sun in the sky. The power loss through the long focal length is disadvantageous.
Furthermore, a large linear reflector for gaining solar energy is shown in the U.S. Pat. No. 4,131,336. The Fresnel structure is here entered into a formed and stabilized earth floor and the reflection is made possible through polymer foils coated with aluminum and placed over the earth floor. Disadvantageous in the context of this Fresnel structure is the high power loss based on the high component part of non-directed reflection.
The large expenditure and the construction sizes for obtaining the reflecting structure are disadvantageous in connection with the previously cited applications, which prevents a large field of application.
It is an object of the present invention to furnish a simple Fresnel structure, which can be easily and automatically produced and can be employed for wide application in the use of solar energy or as a reflector in the illumination industry.